Paper Properties: Gloss

The glossiness of paper is a technical index to evaluate the ability of paper surface to reflect light. Gloss index is mainly used to evaluate coated paper, such as coated paper and cast coated paper. The glossiness of paper is mainly determined by the paper surface sizing material and process.

The instrument for measuring the glossiness of paper is a specular gloss meter. The principle is to use a standard white light source to incident at angles of 20°, 45°, and 75° to the vertical line of the paper, and then use a light receiver to receive it along the reflection direction. The percentage of light intensity compared with the standard is its gloss.

Generally speaking, the glossiness of paper is related to the smoothness of paper, but these two different concepts should not be confused.

The effect of paper gloss on printing is that the high gloss of paper makes the printed matter appear bright and full in color. The chromatic ink for printing is transparent, and the light penetrates the ink to reach the surface of the paper. The paper has high gloss, strong reflected light energy, and looks full of color. However, when printing text on high-gloss paper, most of the area on the page is white paper, and only a small part is covered by text lines. Strong reflections will make the eyes tired and unsuitable for reading.

Generally, color printing, packaging, outdoor advertising, signage and other printed matters that require strong color saturation and visual effects are printed on high-gloss paper.